agreed, the traits on Ancestry aren't that useful. Some of mine were accurate (yeah I have blue eyes) others questionable.
Genetic testing for medical conditions is pretty expensive - there are various providers out there. Once your get Ancestry results, you are free to request your raw Ancestry DNA date, and could upload this to other sites which can offer information on your predisposition to certain conditions. These vary in price - and reliability.
Keep in mind that your Ancestry DNA isn't a whole genome sequence, but instead a snapshot of about 0.1% of your whole genome. So a lot of stuff isn't actually tested. Proper genetic testing is more extensive, and looks specifically at many of these SNPs (single nucleotide polymorphisms) that confer risk in certains genes, eg BRCA gene, AP0E4 gene. But again it can be quite expensive.
Good luck!